Sodium Hydroxide → 4-Methyl-3-cyclohexene-1-carboxylic Acid

To a solution of 4-methylcyclohex-3-enecarbonyl chloride (2 ml) in a mixture of methanol (20 ml) and tetrahydrofuran (20 ml) was added aqueous sodium hydroxide (4N, 20 ml). The resultant mixture was stirred at ambient temperature for 1 hour, and evaporated. The residue was taken up into a mixture of water and ethyl acetate and adjusted pH to around 1. The organic layer was separated, washed with brine, dried over magnesium sulfate, and evaporated under reduced pressure to give 4-methylcyclohex-3-enecarboxylic acid, which was used without further purification.